Belt hole cutter

ABSTRACT

A ROTATIVE HOLE CUTTING DEVICE FOR A HEAVY, SOMEWHAT SOFT, RESILIENT, FABRIC-LIKE MATERIAL IN THE NATURE OF BELTING IS PROVIDED WITH A FORWARDLY-EXTENDING DRILL STEM THAT FIRST ENTERS THE MATERIAL, AND WITH A PAIR OF OPPOSED, ESPECIALLY-CONSTRUCTED AND POSITIONED KEY-LIKE CUTTER ELEMENTS THAT FOLLOWS THE DRILL STEM AND QUICKLY AND EFFICIENTLY CUT-   OUT A CIRCULAR HOLE IN THE MATERIAL. THE DRILL STEM SERVES TO GUIDE MOVEMENT OF THE CUTTER ELEMENTS AND TO RETAIN THE PART OR FRAGMENT BEING CUT-OUT IN POSITION UNTIL THE COMPLETION OF THE OPERATION.

J. A. PARENTI BELT HOLE CUTTER Feb. 6

Original Filed Sept. 17, 1968 INVENTOR JOSEPH A. PARENTI HIS A TTORNE YSUnited States Patent 3,714,690 BELT HOLE CUTTER Joseph A. Parenti, Rte.7, R0. Box 330, Morgantown, W. Va. 26505 Original application Sept. 17,1968, Ser. No. 760,176, new

Patent No. 3,504,577. Divided and this application Sept.

30, 1969, Ser. No. 862,360

Int. Cl. B26d 1/12 US. Cl. 29-105 A 5 Claims ABSTRACT OF THE DISCLOSUREA rotative hole cutting device for a heavy, somewhat soft, resilient,fabric-like material in the nature of belting is provided with aforwardly-extending drill stem that first enters the material, and witha pair of opposed, especially-constructed and positioned key-like cutterelements that follow the drill stem and quickly and efficiently cutout acircular hole in the material. The drill stem serves to guide movementof the cutter elements and to retain the part or fragment being cut-outin position until the completion of the operation.

This application is a division of my application Ser. No. 760,176, filedSept. 17, 1968 now Pat. No. 3,504,577, and entitled Belt Hole Cutter.

The invention relates to accurately cutting-out or forming hole portionsin a relatively tough, somewhat resilient, rather heavy fabric materialand particularly, to a driven cutting tool or device for quicklycutting-out somewhat closely spaced-apart circular holes in a piece ofbelting material to enable mounting the piece as a side skirt for use,for example, with continuous coal mining machinery, such as buggies, ortire cars unloading into a tail piece, thus to limit spillage of coalfrom a conveyor employed therewith.

Although several manufacturers have produced and offered so-called tailpieces for sale to users of continuous belt line systems fortransporting coal out of mines, mine owners prefer to make their ownfrom used or discarded (usually resin or rubber-impregnated) fabric-likebelting which has been worn to an extent requiring replacement. Thisused belting is preferred for reasons of lessened expense andout-lasting skirts made of rubber alone; a conveyor belt made type has amuch longer wear in usage. For example, a purchased rubber type of skirtfor tail pieces may last thirty days, as compared to the three or fourmonths life of a conveyor belt made type. To mount a tail piece on aconveyor or like equipment, it is necessary to cut-out a series ofsomewhat-closely spacedapart holes therealong to receive clampingassemblies. Tail pieces are mounted at one vertical level on the end ofthe equipment to prevent coal from spilling-off and when their bottomedges are worn-down, are then dropped a requisite distance to make themeffective for continued usage.

It has also been customary to provide three sizes of holes, namely, 2",1%" and 1%". Difiiculty has heretofore been encountered in cutting suchholes in view of thenature of the belting material. Exemplary pieces ofsuch material may have about five layers of resin or rubber impregnatednylon fabric with thickened resin or rubber top and bottom layers. Theresilient or somewhat l 3,714,690 Patented Feb. 6, 1973 flexible natureof the material tends to cause an uneven cut and to set up excessiveresistance-generated heat, such that cutters or saws tend to run hot. Acircular saw will burn up, due to the fact that there is too muchfriction, while a single conventional cutter, such as used with wood,results in an off-center or eccentric cutting action due to a periodicholding and releasing of the cutter by the resilient material.

It has thus been an object of the invention to devise a novel cuttingtool or device and cutter elements therefor which will eliminate thedilfculties hereto encountered in providing holes in a fabric-likematerial such as belting;

Another object has been to provide a cutting tool or device having apreliminarily insertable element for aligning the tool, accuratelyguiding it in its cutting action, and retaining the part being cut inposition until the operation is completed;

Another object of the invention has been to devise key-like cuttingelements for a hole cutting tool which will be effective and efficientin cutting a circular part or piece out of a heavy somewhat resilientfabric material such as belting;

A still further object of the invention has been to provide a circularhole cutting tool or device that can be connected to a rotating motormeans, such as an impactor, for quickly and effectively cutting outholes in a somewhat heavy resilient fabric material;

A still further object of the invention has been to devise cutterelements that can be effectively used for cutting symmetrical holes in afabric material without generating appreciable heat, without tearing ordamaging the material and generally, with minimized energy requirements,to quickly and effectively cut-out a circular hole of a desireddiameter;

These and other objects will appear to those skilled in the art from theillustrated embodiment and the claims.

In the drawings, FIG. 1 is a longitudinal side view to scale of acutting tool or device constructed in accordance with the invention;

FIG. 2 is a top plan view of the device on the scale of FIG. 1 withcutter keys omitted for better illustration of the tool head;

FIG. 3 is a fragmental longitudinal side view on the scale of FIG. 1 buttaken at substantially right angleslaminations and with a large size ofhole cut therethrough,

as effected by a cutting tool or device of the invention;

FIG. 6 is a horizontal fragment showing details of the construction andmounting of a key-like cutter element; this view is on the same scale asand is taken along the line VIVI of FIG. 1;

And, FIG. 7 is a perspective view on the scale of FIG. 1 furtherillustrating the construction of each key-like cutter element.

The problem has been solved by providing at least a pair ofdiametrically-opposed and spaced-apart key-like cutter elements 25 of anovel shape and construction and mounting them to extendendwise-forwardly from a tool head 16 on opposite sides of acentrally-positioned, endwise-forwardly-extending twist drill guide stemor element 20 for circular movement with the drill stem that serves as alongitudinal axis for the rotative movement. The drill stem 20 has agreater forward extent to first enter and drill through the center of acircular disc or part that is to be cut-out or removed from beltingmaterial 10. The cutter elements 25, themselves, will thereafter engagethe belting material and start their cutting action. The tool assemblyshown has a longitudinallyextending, solid cylindrical body, drive shaftor stem 15, a hexagonal wrench fiat a at its back end, an enlargedcircular head flange 15b at its forward end, and a central axial socket15c for receiving and carrying the central guiding drill stem 20. Aknurled head 16 is removablysecured on the head flange 15b and about thesocket portion 150 and has at least two forwardly-open,diametrically-oppositely-positioned, keyway slot portions 16a forreceiving a pair of the especially constructed key-like cutter elements25.

It is preferable, in order to enable the tool to be used to cut, asdesired, one of all three diameter sizes, indicated in FIG. 4 as 16a,16b and 160, to provide four key- -way slot portions of rectangular orpolygonal section represented by pairs of opposed slots 16a and 16a.Each slot has a circumferentially-equally-spaced or quadrant locationabout the forward face of the tool head 16. The hexagonal wrench flat15a of the shaft 15 is adapted to receive, for example, a 1%" socketadaptor which will enable it to be connected to the operating shaft ofreversible motor, such as a conventional impact motor (not shown).

In employing the cutting device, a wood board may be placed on the backside of a piece of belting 10 and the device then rotated, eitherclockwise or counterclockwise, by the impact motor to first drill acentral guide hole through the belting. It has been determined that thisis important in providing an accurate centering guide for the operationand in retaining the circular portion being out in position until theactual cutting operation is fully accomplished by the key-like cutterelements 25., A pair of opposite key-like cutter elements 25 areremovablysecured in a pair of opposed keyway slot portions 16a or 16a inthe head 16 of the tool to project endwise-forwardly thereof from theface of the head. The keyway slots are radially-spaced with respect tothe central axis of the device or of the central drill element 20carried thereby. Each keyway slot has at least a leading face providedwith a slope that defines an angular relation with the longitudinal axisof the tool and the central drill element 20 that is a backward slopefrom the standpoint of the selected direction of rotation of the cutter25, clockwise or counterclockwise. If the tool is to provide for bothclockwise and counterclockwise rotation, then each keyway slot 16a and16'a will have both its opposed leading or front and its trailing orback faces sloped to diverge upwardly-outwardly to accommodate backwardtilt of an associated cutter 25 for each direction of tool headrotation.

As shown in the drawings, each key-like cutter element or insert 25 hasa rectangular (polygonal) mounting shank or base 25a and a cutting bladeextending longitudinaily-axially forwardly thereof. The blade is definedby faces 25b, 25c, 25d, 25:: and 251. The faces 25b and 25c represent apair of opposed wide side faces that are adapted to face diametricallyor radially in their mounted relationships in the tool head 16. Thefaces 25d and 25e represent a pair of opposed leading 01' front andtrailing or back narrow edge faces, and 25] represents a beveled orsloped knife face that extends between the narrow edge faces 25d and 25aand along the wide side faces 25d and 250. The knife face 25f is shownformed on the wide side face 25b; it slopes forwardly with respect tothe opposed wide side face 25c to define a surmounting, crossextendingknife edge 25g. As indicated, the knife edge 25g declines backwardlyfrom an apex 25h at the leading edge or edge face 25d towards thetrailing edge face or edge 25a and represents a forward end convergenceof the wide side faces 25d and 250, as accomplished by the beveled orforwardly-declining knife face 25 A slight in-slope or inclination isprovided transversely of wide side faces 25b and 250 that produces aslight planar convergence from the leading edge face 25d towards thetrailing edge face 25s and thus, provides a blunter or slightly widerthickness of the leading edge face 25d. This convergence may be about 1to 2 on each side face for a total of about 2 to 4. It will the notedthat the longitudinal extent of the blade, as represented by its sideand edge faces, is about twice the thickness of the material 10 that isto be cut-out, and that the forward extent of the knife face 25) isabout one-half the thickness of the material 10 to be cut-out.

It has been determined that a centrally-located top cutting apexrepresenting an axially-pointed cutting end is not practical for thecutter elements 25, in that it produces a squeezing action on thematerial and greatly increases frictional resistance and heat. Using apair of oppositelypositioned key-like cutting elements 25 of the presentinvention with an impact motor operating at 1800 r.p.m., a hole 10a canbe smoothly cut through belting 10 in about thirty seconds and withoutraising the temperature of the cutting elements above a temperature atwhich a human finger would be burnt by touching them.

The cutting knife edge 25g that declines backwardly from the apex orhighest corner 2511 and between the leading edge face 25d and thetrailing edge face 25e has a critical backwardly-declining angularrelation b (see FIG. 3) within a range of about 55 to with an optimum ofabout 60". This angle represents the slope of the surmounting forwardend cutting edge 25g in a circumferential or rotative direction, asmeasured from the longitudinal axis or center line of the cutter element25. Also, a so-called lag angle a should be provided within a range ofabout 5 to 12, with an optimum of 10, in the sense of backward tilt ofthe leading edge side 25d of each key element 25 with respect to thelongitudinal axis of the tool and of its central drill stem 20. Theangular relation 0 provides a relief in depth to minimize friction andfrictionally generated heat and resistance to ro'ta tion of the cuttingelements 25. The angular relation b is essential in cleaning the beltmaterial as the cutting operation proceeds; the angular relation a isessential t minimize friction and to provide a smooth concentric cuttingaction without shimmy, flutter or vibration of t e impact motor. Thebackward sloped or following positioning of the cutter keys 25 withrespect to the longitudinal axis of the central drill stem 20 producesimproved results, but is not essential.

As shown in FIG. 1, the knife face 25f of each keylike cutter element 25has a side sloped or angular relationship between opposed wide sidefaces 25b and 256, as represented by c, that is within a range of about10 to 30 with respect to the longitudinal axis of the cutter element. Anoptimum angular relation for c is about 15 this angular relation gives arelief in depth during the cutting operation and as employed with theuse of a thicker, wider or blunter leading edge cutting edge 25d, ascompared to the trailing edge 25c. As illustrated in FIGS. 1 and 7, theopposed wide side faces 25b and 25c and the opposed leading and trailingfaces 25d and 25e are planar; thus, as shown in FIG. 6, each element 25presents a polygonal section of planar sides, as distinguished from acurvilinear section conforming with the periphery of the tool head 16.

It will benoted that the radial positioning of the keyway pairs 16a and16'a may be employed to provide different diameter cutting by the sameset or pair of cutter keys 25. As shown in FIG. 2, the keyways 16'a arelocated at a greater radial distance from the axial center of the toolor its knurled head 16 than the keyways 16a and will thus provide alarger size or diameter of hole than the set 16a, if the same set orpair of cutter keys 25 is used.

In employing four keyways in the tool head 16, one pair or set of cutterkeys may be used in one pair or set f keyways 16a for two differentdiameter sizes, by removing them from the keyways and reinserting themwith their wide sides 25b and 25c reversed from their previouspositioning. In this connection, the rotation of the cutter head 16 willbe reversed, and a mounted backward tilt of the key-like cutter elements25 is assured for both a forward and a reverse direction of movement bygiving each keyway slot a backward-outward slope outwardly on both itsopposed front and back faces. A third diameter of cut may be obtained byusing the same pair of cutter elements 25 within the second-set or pairof opposed keyway slots 16a within which the cutter elements 25 may betilted for either forward or reverse rotation. Also, a second pair ofcutter elements 25 may be provided having a different offsetting oftheir cutting blades to provide a different diameter of cut for eitherforward or reverse tool rotation in, for example, the first set ofkeyway slots 16a. If a third set of keys 25 of the same generalconstruction is provided, then three diameter sizes of holes can bedrilled using one set of keyways 16a and the same direction of rotation.

The guide or pilot drill 20 shown in the drawings is a right hand bit,thus if the cutter elements 25 are set f r counterclockwise cuttingaction in the head 16, the tool should be first rotated clockwise untilthe drill 20 is through the belt; at this time, the tool may then bereversed for counterclockwise operation during which the cutter elements25 will engage and then bore-out a hole a in the belting material 10. Onthe other hand, if a left-hand drill 20 is substituted and used, thenthe tool may be rotated counterclockwise throughout its entire operationfor both the drilling of the guide or pilot hole in the material and thecutting-out of the full size hole 10a therein by the cutter elements 25.

The 55 to 80 angular range of b is critically important, as below 55there is a driving-tearing rather than a cutting action of the keyelements 25 and above 8 0 there is a jackhammering or flutteringrotating actlon. The use of a leading edge 26d that is thicker or moreblunt than the trailing edge 25e is important to provide a relief indepth action in the fabric material 10 that is being cut. The belt holecutter device has greatly speededup and simplified the cutting of holesof suitable size by the workmen in a fabric belt. It eliminateshammering and other complicated procedures, such that tail pieces can ecompletely made from a piece of conveyor belting with a saving of twohours per section.

For removably-securing the cutting keys 25 in their keyways, Allen headset screws 18 and 18 are shown threadably mounted to extend radiallythrough the wall of the head 16. Set screw 17 extends through the wallof the socket portion c to removably-secure the drill element 20therein, and set screw 19 extends transversely or radially through thehead 16 to removably-secure it on the flange 15b and about the socket15c.

Although a preferred apparatus embodiment of the invention has beenshown and described, it will be apparent to those skilled in the artthat various changes, omissions and additions may be made in suchembodiment without departing from the spirit and scope of the inventionas indicated by the claims.

I claim:

1 In a keylike cutter element for endwise-for-ward proyection in abalanced relation from a tool head for cutting-out a hole in a toughsomewhat resilient material by rotative advance into and through thematerial, a polygonal-shaped mounting shank, a cutting blade extendingendwise-longitud inally forwardly of said shank, said blade having abody provided with a pair of opposed planar wide side faces and a pairof opposed planar leading and trailing relatively narrower faces, saidleading narrower face being slightly wider than said trailing narrowerface, said blade having a substantially planar knife face at the forwardend of one planar wide side face, said planar knife face decliningforwardly from said one wide side face into the other opposed said wideside face along and between said leading and trailing narrower faces todefine a surmounting knife edge, and said lknife edge decliningbackwardly along the other opposed said wide side face to said trailingnarrower face from a forward apex immediately at said leading narrowerface in an angular relation of between about 55 to with respect to alongitudinal axis of the element.

2. In a cutter element as defined in claim 1, said knife face definingan angle of about 10 to 30 between said opposed wide side faces withrespect to the longitudinal axis of the element.

3. In a cutter element as defined in claim 1, said wide side facesconverging from said leading narrow face towards said trailing narrowerface within a total of about 2 to 4.

4. In a keylike cutter element for endwise-forward projection in a"paired diametrically opposed spaced-apart balanced relation from a toolhead to cut-out a hole in a fabriclike material by rotative advance intoand through the material, said cutter element having a mounting shank ofpolygonal section and a cutting blade extending longitudinally-forwardlyof said shank, said cutting blade having a body provided with a pair ofopposed planar wide side faces and a pair of opposed planar leading andtrailing narrower faces that are immediately connected alonglongitudinal corners with said pair of opposed planar wide side faces, aplanar knife face at a forward end of said body sloping from one wideside face into the other opposed said wide side face immediately betweenand along said leading and trailing narrower faces and defining an apexat the leading narrower face, said knife face being surmounted by aknife edge that extends from the apex at said leading narrower face in abackwardly declining relation along said knife face to said trailingnarrower face and having an angular relation with respect to alongitudinal axis of the cutter element of about 55 to 80, said knifeface defining an angular relation between said opposed wide side facesof about 10 to 30 with respect to the longitudinal axis of the cutterelement, said leading narrower face being of thicker section than saidtrailing narrower face with said opposed wide side faces converging fromsaid leading face toward said trailing face, and said shank beingadapted for mounting in the tool head in a backwardly-tilted relationwith respect to the apex of said knife edge that defines an angle ofabout 5 to 12 with respect to a longitudinal axis about which the cutterelement is to be rotated in its utilization.

5. 'In a cutter element as defined in claim 4, said convergence of saidwide side faces being within a total of about 2 to 4.

References Cited UNITED STATES PATENTS 2,392,001 1/1946 Raper 29'952,406,442 8/1946 Smith 77-79 2,596,110 5/1952 Adrian 2996 2,645,471 7/1953 King 29'95 X 3,233,306 2/ 196 6 Kessel et al. 2995 FOREIGN PATENTS1 1 8,935 9/ 1944 Australia 29-95 441,935 1/ 1968 Switzerland 29--95HARRISON L. HINSON, Primary Examiner

